Fix for x32 by removing 'q' suffix in x86-64 instructions

Fix for x32 by removing 'q' suffix in x86-64 instructions
(Apply commit 711f7fe from 'master' branch)

We do not need the 'q' suffix on x86_64 atomic instructions for AO_t
which is defined as "unsigned long"; the later is 32-bit for x32
and 64-bit for x86-64; the register operand in x86-64 atomic
instructions is sufficient to properly determine the register size.

* src/atomic_ops/sysdeps/gcc/x86_64.h (AO_fetch_and_add_full,
AO_and_full, AO_or_full, AO_xor_full, AO_compare_and_swap_full,
AO_fetch_compare_and_swap_full): Remove 'q' suffix in asm instruction.